Answer: 7
Explanation:
Before a number but after a decimal. The zeros at the end would usually mean that it doesn't count but since the numbers are before the zeros and after a decimal it's 7 sig figs
Answer:
2Li(s) + ⅛S₈(s, rhombic) + 2O₂(g) → Li₂SO₄(s)
Explanation:
A thermochemical equation must show the formation of 1 mol of a substance from its elements in their most stable state,.
The only equation that meets those conditions is the last one.
A and B are wrong , because they show Li₂SO₄ as a reactant, not a product.
C is wrong because Li⁺ and SO₄²⁻ are not elements.
D is wrong because it shows the formation of 8 mol of Li₂SO₄.
Answer:
310.53 g of Cu.
Explanation:
The balanced equation for the reaction is given below:
CuSO₄ + Zn —> ZnSO₄ + Cu
Next, we shall determine the mass of CuSO₄ that reacted and the mass Cu produced from the balanced equation. This can be obtained as follow:
Molar mass of CuSO₄ = 63.5 + 32 + (16×4)
= 63.5 + 32 + 64
= 159.5 g/mol
Mass of CuSO₄ from the balanced equation = 1 × 159.5 = 159.5 g
Molar mass of Cu = 63.5 g/mol
Mass of Cu from the balanced equation = 1 × 63.5 = 63.5 g
Summary:
From the balanced equation above,
159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.
Finally, we shall determine the mass of Cu produced by the reaction of 780 g of CuSO₄. This can be obtained as follow:
From the balanced equation above,
159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.
Therefore, 780 g of CuSO₄ will react to produce = (780 × 63.5)/159.5 = 310.53 g of Cu.
Thus, 310.53 g of Cu were obtained from the reaction.
C.
Explanation:
As a pendulum swings from its highest to its lowest position along an arc, what happens to its kinetic energy and potential energy? The potential energy decreases while the kinetic energy increases.
Answer:
C₂H₈N₄O₆ is the molecular formula for the compound
Explanation:
Data from the problem:
13 g of C in 100 g of compound
4.3 g of H in 100 g of compound
30.4 g of N in 100 g of compound
52.2 g of O in 100 g of compound
Firstly we determine, the mass of each in 184 g of compound, which is 1 mol
(13 g / 100 g) . 184 g = 24 g C
(4.3 g / 100 g) . 184 g = 7.91 g H ≅ 8 g H
(30.4 g / 100 g) . 184 g = 56 g N
(52.2 g / 100 g) . 184 g = 96 g O
And now, we divide the mass by the molar mass of each to determine the moles:
24 g C / 12 g/mol = 2 mol C
8g H / 1 g/mol = 8 mol H
56 g N / 14 g/mol = 4 mol N
96 g O / 16 g/mol = 6 mol O
So the molecular formula of the compound is C₂H₈N₄O₆
